Expert opinion regarding other categories of witness

9.159 In addition to children, in DP 69 the Commissions raised whether there is also a need to clarify the admissibility of expert opinion as ‘counter-intuitive’ evidence in other instances.[193] Similar themes are discussed above in relation to preconceptions about the behaviour and development of children.

9.160 The Commissions asked whether the uniform Evidence Acts should be amended to provide for the admissibility of expert opinion evidence in relation to witnesses such as victims of family violence or people with an intellectual disability that is directly relevant to the facts in issue or to the credibility of witnesses.[194]

Submissions and consultations

9.161 The NSW DPP supports such an amendment.[195] The amendment is said to be a useful step in rectifying ‘gaps and misunderstandings in allegedly common or general knowledge’ about human behaviour.[196]

9.162 The Criminal Law Review Division of the New South Wales Attorney General’s Department supports Proposal 11–6, saying it is fundamental that the court be able to assess all the evidence accurately, which requires understanding of ‘the particular nature of the intellectual disability’ a witness has in assessing the credibility of the witness. Otherwise, certain mannerisms or difficulty in recalling details may lead to unfounded doubt about the credibility of the witness.[197]

9.163 Other support is qualified. Women’s Legal Service Victoria supports ‘in principle’ an affirmative answer to Question 8–2 as it relates to ‘the credibility and reliability of victims of family violence’, but adds:

However, we believe that very great care would need to be taken in the drafting of any such provision to ensure that it did not increase the risk of victims of violence being seen as unreliable witnesses. It should not be possible, for example, for the provision to be used by an alleged perpetrator of violence to raise questions of credibility and reliability of evidence of victims of violence, merely on the basis of their being a victim of violence. If the provision cannot be clearly directed and limited in this way, then it should not be introduced.[198]

9.164 Opposition was received from Victoria Police, stating that it is ‘a matter for the court to decide on credibility and reliability’ and that operation of the amendment would be unclear.[199]

9.165 The operation of such an amendment also concerns the Law Society of New South Wales, on the basis that it could extend to people who simply have limited education or difficulties of recall but not disability proper.[200]

9.166 The NSW PDO ‘very much oppose[s]’ the amendment for similar reasons to those given for rejecting Proposal 8–1.[201]

The Commissions’ view

9.167 The Commissions are of the view that no compelling case has been made out for any further statutory amendment of the opinion rules as they apply in this area other than as recommended above for children.

9.168 The Commissions note that the Victorian Law Reform Commission (VLRC) concluded in its Defences to Homicide report that expert opinion evidence on family violence, for example, ‘is already admissible under current rules of evidence’, both at common law and under the uniform Evidence Acts.[202] Submissions and consultations summarised by the VLRC generally took the same view.[203] In submissions and consultations on DP 69, no reluctance to admit such evidence was shown that would warrant amendment of the uniform Evidence Acts. Significantly, the wide support for an amendment in relation to child witnesses shown by the individuals, bodies and legislatures referred to above has no counterpart in relation to other categories of witness.

9.169 It is important to keep in mind, however, that the credibility rules provide an obstacle to the admission of evidence where it relates to the credibility of a witness. Recommendation 11–7 recommends amendment of the credibility rule to allow expert opinion evidence to be received about the credibility of witnesses upon satisfaction of certain conditions, but does not limit the class of witness about which such evidence would be admissible. The section would therefore allow expert evidence of the credibility of witnesses other than children to be admitted. These issues are addressed in Chapter 12.

9.170 The reason for recommending a clarification of the expert opinion exception to the opinion rule for children is that, despite the fact that expert opinion evidence about the development and behaviour of children falls within s 79, courts have shown a reluctance to apply the section to such evidence. That appears to be due to a pervasive view that ‘child development and behaviour’ is within the common knowledge of the tribunal of fact. By contrast, there is greater acceptance of the fact that behaviour of victims of crime and those with cognitive impairment is not within common knowledge.

9.171 The Commissions do not recommend any further amendment to s 79.


[193] That is, evidence that is capable of dispelling myths or rectifying erroneous assumptions that may be held by the jury on a particular issue. See Ibid; I Freckelton and H Selby, Expert Evidence: Law, Practice, Procedure and Advocacy (2nd ed, 2002), 16.

[194] Australian Law Reform Commission, New South Wales Law Reform Commission and Victorian Law Reform Commission, Review of the Uniform Evidence Acts, ALRC DP 69, NSWLRC DP 47, VLRC DP (2005), Q 8–2.

[195] Director of Public Prosecutions (NSW), Submission E 87, 16 September 2005.

[196] K Mack, Submission E 82, 16 September 2005.

[197] NSW Attorney General’s Department Criminal Law Review Division, Submission E 95, 21 September 2005. See Rosemount Youth and Family Services, Submission E 107, 15 September 2005.

[198] Women’s Legal Services Victoria, Submission E 110, 30 September 2005.

[199] Victoria Police, Submission E 111, 30 September 2005.

[200] The Criminal Law Committee and the Litigation Law and Practice Committee of the Law Society of New South Wales, Submission E 103, 22 September 2005.

[201] New South Wales Public Defenders Office, Submission E 89, 19 September 2005.

[202] Victorian Law Reform Commission, Defences to Homicide: Final Report (2004), [4.127].

[203] Ibid, [4.118].